Improved marine-propeller



y UNITED STATESv PATENT OFFICEO JOHN B. ROOT, OF BROOKLYN, NENV YORK.

IMPROVED MARINE-PROPELLER..

Specification forming part of Letters Patent No. 38,4 I 5, dated May 5, 1863;' antedated May 3, 1863.

['0 all whom, it may concern.;-

Be it known that I, JOHN B. Boor, of the city of Brooklyn, in the county of Kings and State of New York, have invented a new and Improved Propeller for Vessels and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is a side view of the stern of a canaLboat having my propeller applied Fig. 2, a horizontal section of the same. Fig. 3 is a back View of the propeller.

Similar letters of reference indicate corresponding parts in the several figurrs.

The object of my invention is more particularly to obtain a propeller adapted for canalnavigation, which, besides possessing other advantages, shall be free from the principal objections to the screw-propellers heretofore employed-viz., th at of requiring the after part of the boat to be of such lean form as to seriously impair its carrying capacity; and to this end it consists in the construction of' a propeller with its blades arranged tangentially to circles concentric with a propellershaft placed parallel with the length of and in the center of the vessel, such blades being attached to a hub in such manner as to prevent the water from entering the propeller from the interior--tha-t 'is to say, except by passing in an inward direction from between the outer edges of the blades, and to compel the discharge at the inner edges of the blades, the said hub being preferably made of conical form, for the purpose of directing the water which is discharged from the center ofthe wheel directly astern of the vessel.

To enable those skilled in the art to make and use myinvention, Iwill proceed to describe its construction and operation.

A is the propellershaft running through the stern of the vessel like the shaft of an ordinary screw-propeller. B B are the tangentially-arranged blades attached to the central conical hub, O, in such manner as to prevent the en trance of the water from the front ofthe propeller into the central space within the blades, such attachment being at their front or inner ends, and their outer ends being connected together by a ring, D, which serves to make them mutually supporting. The said tangential blades in the propeller represented may be considered as arranged around an imaginary truncated cone, the truncated end of which is next to the stern of the vessel, and hence they have a slight twist somewhat resembling that of the blades of a screw, and l consider this arrangement the best, but they might be arranged around an imaginary cylinder, in which case they would be straight and parallel with the axes of the sha-ft, the tangential arrangement being retained. The front of the hub, which is the base of its own cone, and coincides with the truncated end of the imaginary cone around which the blades are arranged, is intended to work as close as practicable to a flat surface formed upon the stern of the vessel, and the hub should be made hollow to give buoyancy to the propeller.

The peculiarity in the action of this propeller, in which it differs from that of the screw-propeller, is that the blades take the water from the outside, and discharges it in a column at the center directly astern of the vessel, and it is by that Ineans that the necessity of making the vessel with what is termed a leam run77 is obviated, and the stern is allowed to be made broad enough below the water-line to allow room for the propellingengine in the extreme after part of the vessel, thereby obviating in the greatest possible degree the reduction of the carrying-capacity by the application of steam-propulsion.

The above -mentioned action of the propeller also, when it is applied to canal-navi` gation, prevents the water which is thrown back from washing the banks; and the said action also allows the vessel to be loaded so that its bottom comes nearer to the bottom of the canal, as all the water to be displaced can be obtained from the sides of the vessel. By making the hub of conical form-that is to say, with a conical surface tapering away from the stern of the vessel-the water discharged at the center of the wheel striking the said said surface is caused to be discharged more directly astern and in a more compact column than if all the waterv taken into the propeller were collected in a body within the center of I the propeller itself, where the meeting of the Waters at a comparatively obtuse angle would to some extent retard the discharge in a rearward direction.

This propeller may be entirely or partly submerged.

What I claim as my invention, and desire to secure by Letters Patent, is

The arrangement of the blades and hub of the propeller7 substantially as herein specified, whereby the Water is drawn from the oir; eumferenee toward the center and discharged from the center directly astern of the vessel, as herein set forth.

JOHN B. ROOT.

XVitnesses:

R. GAWLEY, TIMOTHY SHINE. 

